Linaclotide is useful in irritable bowel syndrome with constipation (IBS-C) and chronic idiopathic constipation (CIC). It is a polypeptide and is susceptible to degradation. Stability of linaclotide dosage forms has presented a significant problem to the formulator. Novel and innovative solution to the problem are required because conventional means of stabilizing a polypeptide have not worked. For example, the label (product information) for presently marketed product, Linzess® capsules, discloses that the product contains a combination of L-leucine and calcium chloride dihydrate which are one of the novel combination of stabilizers claimed in the U.S. Pat. No. 8,748,573. Further the label for Linzess® capsules instructs that the product should be stored at 25° C. (excursions permitted between 15° C. and 30° C.) and further instructs to protect the product from moisture and cautions not to remove desiccant from the container. It is apparent from the literature that linaclotide possesses intrinsic chemical instability (for example, induced by moisture-driven degradation reactions such as hydrolysis, oxidation, deamidation, isomerization, and multimerization) and there lies a need for providing a novel method of preparing a stable solid dosage form of linaclotide with an improved shelf life and robust stability profile.